• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>RSC Advances >Characterization and acid-catalysed depolymerization of condensed tannins derived from larch bark
【24h】

Characterization and acid-catalysed depolymerization of condensed tannins derived from larch bark

机译：落叶松树皮衍生的浓缩单宁的表征和酸性催化的解聚

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Condensed tannins from larch bark extracts are a natural renewable and eco-friendly material and are potential substitutes for phenolic petrochemicals. However, the wide application of tannin is restricted by its low reactivity. Therefore, the goal of this study was to enhance the reactivity of larch tannin by depolymerization and determine optimal reaction conditions. The structures of larch tannin and depolymerized larch tannin were characterized by Fourier transform infrared (FT-IR) spectroscopy, solid phase C-13-NMR and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry. The thermal stability of larch tannin before and after depolymerization was evaluated by thermogravimetric analysis (TGA). The results indicated that the monomeric units of larch tannin were mainly composed of catechin/epicatechin, gallocatechin/epigallocatechin, catechin-gallocatechin esters, and stilbene glucosides. The presence of a catechin gallate dimer that had lost both gallic acid residues and a hydroxy group and a small amount of fisetinidin units were also observed. Additionally, a series of peaks corresponding to oligomers of larch tannin of up to 11 repeating units were observed from the MALDI-TOF MS data. Depolymerization treatment, especially using 2-mercaptoethanol as a nucleophilic reagent, was found to be beneficial to the enhancement of thermal stability. The optimization of the depolymerization reaction allowed the reaction to be completed in two hours, at 60 degrees C, using 2-mercaptoethanol as a nucleophile and 0.1 mol L-1 HCl. Many compounds of molecular weight less than 600 Da, mainly dimers and monomers, were obtained under these reaction conditions.
机译：来自Larch Bark提取物的浓缩单宁是天然可再生和环保的材料，是酚类石化的潜在替代品。然而，单宁的广泛应用受其低反应性的限制。因此，本研究的目的是通过解聚并确定最佳反应条件来提高落叶松单宁的反应性。落叶松和解聚的落叶松的结构是傅里叶变换红外（FT-IR）光谱，固相C-13-NMR和基质辅助激光解吸电离飞行时间（MALDI-TOF）质谱法的特征。通过热重分析（TGA）评价解聚前后落叶松的热稳定性。结果表明，落叶松单宁的单体单位主要由儿茶素/表情川岛，加法子素/ ePigallocateChin，儿茶素 - 寄生虫素酯和芪葡萄糖苷组成。还观察到已经失去了无碱酸残基和羟基和少量Fisetinidin单元的儿茶素粘滞二聚体的存在。另外，从MALDI-TOF MS数据中观察到与高达11个重复单元的落叶松单宁的低聚物对应的一系列峰。发现解聚处理，特别是使用2-巯基乙醇作为亲核试剂，有利于增强热稳定性。通过2-巯基乙醇作为亲核试剂和0.1mol L-1 HCl，优化解聚反应的优化在60℃下以60℃完成反应。在这些反应条件下获得许多分子量，主要是二聚体和单体的分子量大于600ds。

著录项

  • 来源
    《RSC Advances》 |2017年第56期|共12页
  • 作者

    Zhang Aibin; Li Jiongjiong; Zhang Shifeng; Mu Youbing; Zhang Wei; Li Jianzhang;

  • 作者单位

    Beijing Forestry Univ MOE Key Lab Wooden Mat Sci &

    Applicat Beijing Key Lab Wood Sci &

    Engn 35 Qinghua East Rd Beijing 100083 Peoples R China;

    Beijing Forestry Univ MOE Key Lab Wooden Mat Sci &

    Applicat Beijing Key Lab Wood Sci &

    Engn 35 Qinghua East Rd Beijing 100083 Peoples R China;

    Beijing Forestry Univ MOE Key Lab Wooden Mat Sci &

    Applicat Beijing Key Lab Wood Sci &

    Engn 35 Qinghua East Rd Beijing 100083 Peoples R China;

    Chinese Acad Sci CAS Key Lab Biobased Mat Qingdao Inst Bioenergy &

    Bioproc Technol Qingdao 266101 Peoples R China;

    Beijing Forestry Univ MOE Key Lab Wooden Mat Sci &

    Applicat Beijing Key Lab Wood Sci &

    Engn 35 Qinghua East Rd Beijing 100083 Peoples R China;

    Beijing Forestry Univ MOE Key Lab Wooden Mat Sci &

    Applicat Beijing Key Lab Wood Sci &

    Engn 35 Qinghua East Rd Beijing 100083 Peoples R China;

  • 收录信息
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 化学;
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号